The present technology relates to an imaging device, to an electronic apparatus that includes the imaging device, and to a method of manufacturing an imaging device.
An imaging device such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) has been widely used for, for example, a digital still camera, a digital video camcorder, and the like. Such an imaging device may include, for example, a photodiode, and a signal reading circuit that reads a photoelectric conversion signal obtained by the photodiode to outside, for each pixel. The signal reading circuit may include, for example, a transfer transistor, an amplifier transistor, a reset transistor, a selection transistor, and the like (for example, see Japanese Unexamined Patent Application Publication No. 2008-91788 (JP2008-91788A)). These transistors may be shared by a plurality of photodiodes in some cases.
In order to achieve low illuminance characteristics equivalent to those of an existing image sensor having ultra-high sensitivity, it is desired to reduce capacity in the signal reading circuit and to improve conversion efficiency of the imaging device. In existing technologies, for example, p-type impurity concentration of a well layer in contact with a FD (Floating Diffusion) section or n-type impurity concentration of the FD section is decreased to suppress p-n junction capacity (for example, see JP2008-91788A and Japanese Unexamined Patent Application Publication No. 2008-218756 (JP2008-218756A)). Moreover, for example, insulating films are provided on both sides of the FD section to suppress the p-n junction capacity (for example, see Japanese Unexamined Patent Application Publication No. 2012-119492 (JP2012-119492A)).